1. Field of the Invention
The present invention relates to exercise machines. More particularly, the present invention relates to exercise machines designed to shape and strengthen the gluteal and hamstring muscles.
2. Description of the Related Art
Human gluteal muscles perform a variety of important functions, the most noteworthy being hip joint movement. Although the importance of strong gluteal muscles to athletes, including serious bodybuilders and runners and the like, is self-evident, strong gluteal muscles are important for virtually everyone. So that one may fully understand the foregoing, as well as the advantages of the present invention, set forth below in this section is a detailed description of the anatomy and the kinesiology of, and prior art exercises for, the gluteal muscles.
With respect to anatomy, the gluteal region, or "buttocks", comprises the posterior muscles on each side of the human hip. The muscles of the gluteal region responsible for hip extension and hyperextension include the well-known gluteus maximus, as well as a number of other, smaller, muscles: the gluteus medius, the gluteus minimis, the six deep outward rotators, and the hamstrings. These muscles are discussed briefly and generally below.
The gluteus maximus is generally the heaviest and largest muscle in the human body. The gluteus maximus is also generally formed of the largest size of muscle fibers found in the body. Thus, almost always, the gluteus maximus is the single strongest muscle in anyone's body. The gluteus maximus forms a quadrilateral pad over the protruding bones of the pelvis. It originates at the dorsal surfaces of the ilium bone of the hip and at the sacral bone of the vertebral column, and it inserts along a tract of fibers running down the lateral portion of the thigh. It also inserts into the proximal portion of the femur (or "thigh bone").
Beneath the gluteus maximus are, in increasing order of depth, the gluteus medius and the gluteus minimis muscles. Both the gluteus medius and gluteus minimis muscles are "fan-shaped". The gluteus medius originates at the ilium of the hip and inserts into a large bump (the "greater trochanter") on the proximal end of the femur. The gluteus minimis originates at a small area on the surface of the ilium, and it, like the gluteus medius, inserts onto the greater trochanter.
The piriformis muscle originates at the sacrum and inserts on the greater trochanter. In addition to its importance in movement, discussed below, this muscle is also important because it lies on top of and protects the sciatic nerve where that nerve exits the dorsal surface of the pelvis. Injury to the sciatic nerve can cause loss of ability to contract almost every muscle in the lower leg as well as most of the hamstring muscles.
The obturator internus muscle originates at the pelvic surface and, after exiting the pelvis, inserts on the medial surface of the greater trochanter. The obturator internus muscle comprises two parts, actually separate muscles, called the superior and inferior gemelli.
The quadratus femoris muscle is a flat, short muscle that lies beneath the obturator and gemelli muscles. The quadratus femoris muscle originates on the protruding bone of the pelvis over which the gluteus maximus lies and it inserts into the femur.
The kinesiology; that is, the principles of mechanics and anatomy in relation to human movement; of the gluteal muscles can be briefly described. While the hamstring is the chief extensor of the thigh, the gluteus maximus muscle is a chief extensor of the thigh against a resistance. Via its attachment to the pelvis, the gluteus maximus can also be a good extensor of the back when the thigh is fixed and the hip joint is free to move (e.g., when rising from a seated position). The gluteus maximus also assists in lateral rotation of the thighs. The gluteus medius and gluteus minimis muscles act to abduct (i.e., move away from the center of the body) the thigh at the hip and to medially rotate the thigh at the hip.
Heretofore, a number of exercises and exercise apparatus have been developed to, at least in part, exercise the gluteal and hamstring muscles. Broadly, these can be broken down into free weight exercises and machine exercises. A number of these exercises and exercise apparatus are discussed below.
One of the free weight exercises (that is, exercises that use dumbbells and barbells as opposed to machines) is the straight-legged dead lift. This exercise works the lower back and hamstrings as well as other gluteal muscles. The straight-legged dead lift involves picking up a bar by bending over, grasping the bar, and slowly lifting it by extending both the back and the knees. As the knees approach a full extension, the exerciser should continue to extend the lower back until he is standing in an erect position. The exerciser then can complete this lift by lowering the weight back to the floor by bending at the waist but not at the knees. This exercise involves the erector spinal, three transverospinal, and hamstring muscles as well as the gluteus maximus muscles. If this exercise is done incorrectly, by, for example, bending the knees during the descent portion of the exercise, the gluteus maximus muscle is not fully stretched and the amount of its development is not optimized.
A second free weight exercise heretofore used to develop the gluteal muscles is the full squat. This exercise begins with a barbell placed across an exerciser's shoulders with the exerciser's feet about shoulder width apart. With his head up and his back straight, the exerciser should then slowly bend his knees until the top of his thighs are 90.degree. or parallel with the floor. Without bouncing from this position the exerciser should raise to a position just short of locking out his knees, and then he should return to the deep squat position. The full squat is like the dead lift insofar as that it is easy to do in a way that does not maximize gluteal stimulation. For example, if the squat is terminated before the thighs become parallel to the floor, the thighs and not the hip extensors are more strongly activated. Also, it is very easy to perform the full squat in a dangerous manner or the exercise may even be inherently dangerous for some people. For example, persons with short torsos often find that their hips and buttocks raise before their back when attempting to stand up from a deep squat. This can put great stress on the lower back. Accordingly, it is fairly common knowledge among weight lifters that if one has a short torso he should not go extremely heavy in this exercise, or lower back injury may result.
Yet another free weight exercise is the lunge, wherein an exerciser essentially steps deeply forward and then springs back into a standing position while carrying a weight across his or her shoulders. Like the squat, the lunge can put undue stress on the exerciser's lower back. Changing weights is also relatively difficult when performing this exercise.
With respect to exercise machines, a number of companies have developed and market gluteal machines. The Nautilus Company, for example, as well as the Marcy Company and a few others, produce hip and back machines that do produce some toning of the gluteal muscles. However, these machines are not nearly as effective as even the deadlift and squat for developing gluteal strength, power and endurance. Certain inward and outer thigh adductor/abductor machines, including ones manufactured by the Marcy and Paramount companies, are fairly effective in isolating and developing the gluteus medius and the gluteal minimis. The outward movement (hip abduction with outward rotation) is designed to work the gluteus medius and gluteus minimus. Some gyms are also now equipped with a standing thigh extension unit or hip and buttocks machine. With these machines the exerciser holds a bar and extends the thigh and leg (with the knee straightened) directly to the rear as far as possible. It is also possible with some of these machines to move the leg to the front of the body, thereby flexing the thigh. Other machines, "Butt Busters" and the like, require an exerciser to lie on his or her side, and then allow only one side or the other of the gluteal region to be exercised at one time. In using many of these machines it is difficult to ensure rotation is from the hip and not the knee. It is also easy to pull the leg to the side, rather than directly backward, which does not work the gluteus maximus muscle as strongly. Also, these machines can be dangerous in that arching of the lower back during extension of the thigh can create or aggravate lower back injuries.
Based upon the foregoing, it should be clear that the heretofore developed exercises and exercise machines designed to strengthen and tone the gluteal muscles all have a number of shortcomings and differences. They all have one or more of the following defects: they do not effectively isolate the target muscles; they do not effectively stress the target muscles; they are potentially dangerous insofar as they may easily cause injuries in use; and they are relatively ineffective insofar as it is easy to use them incorrectly. Thus, it should be appreciated that there is a great need, unfulfilled by the prior art, for a safe, effective, and easy to use gluteal exercise apparatus.